The present invention relates to a method for connecting between substrates on which a plurality of electrodes are provided, a flip-chip mounting structure and a connection structure between the substrates formed by the connecting method.
In recent years, as a result of growing density of semiconductor integrated circuits (LSIs), circuit boards and electronic components, all of which are used in electronic equipment, an increase in the number of electrodes and a fine pitch of the electrodes are accelerated. Abilities of such as realizing narrow pitch, short tact time, and simultaneous formation of connectors are demanded in the process in which the electronic components are mounted.
To meet the above demand, some of the inventors of the present application disclose as a next-generation mounting method, a flip-chip mounting method using a resin which contains conductive particles and a gas bubble generating agent in WO 2006/103948.
FIG. 13A to FIG. 13D are cross-sectional views for illustrating basic steps of the flip-chip mounting method disclosed in the above publication.
As shown in FIG. 13A, a resin 105 containing conductive particles 106 and a gas bubble generating agent (not shown) is supplied into a space between a circuit board 101 having a plurality of connecting terminals 102 and a semiconductor chip 103 having a plurality of electrode terminals 104. The resin 105 is then heated and gas bubbles 110 are generated from the gas bubble generating agent contained in the resin 105 as shown in FIG. 13B. At this time, the resin 105 is pushed aside by the growing gas bubbles 110 and self-assembled in a space between the connecting terminals 102 and the electrode terminals 104 as shown in FIG. 13C. After that, connectors 107 are formed in the space between the terminals 102 and 104 by further heating the resin 105 and melting the conductive particles 106 contained in the resin 105 which is self-assembled in the space between the terminals 102 and 104 as shown in FIG. 13D. A flip-chip mounting structure in which the terminals 102 and 104 are electrically connected through the connectors 107 is obtained in this way. This method can also be used in, for example, connecting between substrates on which electronic components are mounted.